refactor: 删除 CalcNotionalByMode, 保证金/融资腿计息基数内联到调用点

CalcNotionalByMode 已完成历史使命:
- 融资腿(1/2/9)迁入 FundingLegStrategyFactory
- 保证金(5/6)迁入 MarginModes.Contains 分支
- 死代码(3/4/7/8)已删

调用点(GetInterests:843)现在内联两条路径:
- 保证金: closePrincipal = Fix × closePercent (用 MarginModes.Contains 判断)
- 融资腿: FundingLegStrategyFactory.Get(mode).CalcNotional(...)

删除:
- CalcNotionalByMode 方法(含注释)
- 2个用反射调私有方法的诊断测试(验证的逻辑已被FundingLegStrategyTest覆盖)

验证: 编译0错误, 全量509测试7失败(基线一致)。

UnitTestProject/Modules/SwapModule/SwapUnwindFloatingLegDiagnosticTdd.cs

@@ -66,33 +66,5 @@ namespace YLErp.Modules.SwapModule
                 TradeDate = D0, StartDate = D0, ExerciseDate = D1, TradeStatus = "确认成交", ValidState = "Valid",
                 StockEqvNotional = (double)RealLong, Notional = (double)RealLong, trade_extend = extend };
         }
-
-        /// <summary>用反射调用 private CalcNotionalByMode，直接证明各 mode 的 closePrincipal 是否依赖 posiLong/posiShort。</summary>
-        private (decimal close, decimal posi, decimal pct) CallCalcNotionalByMode(swap_position position, decimal closePct, decimal posiNotional, decimal posiLong, decimal posiShort)
-        {
-            var m = typeof(SwapDealService).GetMethod("CalcNotionalByMode", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
-            return ((decimal, decimal, decimal))m.Invoke(_svc, new object[] { position, closePct, posiNotional, posiLong, posiShort });
-        }
-
-        [TestMethod]
-        public void 诊断_mode9_标的期初全价_closePrincipal_不依赖posiLong_而用posiNotional()
-        {
-            // mode 9 分支：closePrincipal = posiNotional * closePercent
-            var baseP = OrigBasePrice();
-            var (close, posi, _) = CallCalcNotionalByMode(baseP, ClosePct, RealLong * ClosePct, OrigLong, 0m);
-            Console.WriteLine($"[mode9] posiNotional={RealLong * ClosePct} posiLong(orig)={OrigLong} → closePrincipal={close}");
-            Assert.AreEqual(RealLong * ClosePct * ClosePct, close, "mode9 应 = posiNotional(=real剩余*closePct) * closePct，与 posiLong(orig 100M) 无关");
-        }
-
-        [TestMethod]
-        public void 诊断_mode5_预付金_closePrincipal_用自身Fix_不依赖posiLong()
-        {
-            // mode 5 分支：closePrincipal = position.InterestPrincipalFix * closePercent（用 Clone 后的 real Fix）
-            var prepay = RealPrepay(); // Fix = RealFix(66,813.12)
-            var (close, posi, _) = CallCalcNotionalByMode(prepay, ClosePct, RealLong * ClosePct, OrigLong, 0m);
-            Console.WriteLine($"[mode5] Fix(cloned real)={RealFix} posiLong(orig)={OrigLong} → closePrincipal={close}");
-            Assert.AreEqual(RealFix * ClosePct, close, "mode5 应 = 实时腿剩余本金(real Fix) * closePct，与 posiLong(orig 100M) 无关");
-            Assert.AreNotEqual(OrigFix * ClosePct, close, "务必不是期初 99,000 * closePct（证明后端修复生效）");
-        }
     }
 }